//check for bad sectors = 52mins

# time fsck.vfat -v -f -V -w -t /dev/sdd1
fsck.fat 3.0.28 (2015-05-16)
Checking we can access the last sector of the filesystem
Boot sector contents:
System ID "        "
Media byte 0xf8 (hard disk)
       512 bytes per logical sector
     32768 bytes per cluster
       598 reserved sectors
First FAT starts at byte 306176 (sector 598)
         2 FATs, 32 bit entries
   1944064 bytes per FAT (= 3797 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 4194304 (sector 8192)
    485936 data clusters (15923150848 bytes)
63 sectors/track, 255 heads
      8192 hidden sectors
  31108096 sectors total
Starting check/repair pass.
Checking for bad clusters.
Reclaiming unconnected clusters.
Checking free cluster summary.
Starting verification pass.
Checking for unused clusters.
/dev/sdd1: 1040 files, 104131/485936 clusters

real  52m27.358s
user  0m2.918s
sys 1m9.877s



//don't check for bad sectors = 3sec
# time fsck.vfat -v -f -V -w /dev/sdd1
fsck.fat 3.0.28 (2015-05-16)
Checking we can access the last sector of the filesystem
Boot sector contents:
System ID "        "
Media byte 0xf8 (hard disk)
       512 bytes per logical sector
     32768 bytes per cluster
       598 reserved sectors
First FAT starts at byte 306176 (sector 598)
         2 FATs, 32 bit entries
   1944064 bytes per FAT (= 3797 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 4194304 (sector 8192)
    485936 data clusters (15923150848 bytes)
63 sectors/track, 255 heads
      8192 hidden sectors
  31108096 sectors total
Starting check/repair pass.
Reclaiming unconnected clusters.
Checking free cluster summary.
Starting verification pass.
Checking for unused clusters.
/dev/sdd1: 1040 files, 104131/485936 clusters

real	0m3.845s
user	0m0.138s
sys	0m0.227s

